1 / 39

Ecology of Populations

Ecology of Populations. Chapter 46. Chapter Outline. Scope of Ecology Population Density and Distribution Population Growth Models Survivorship Curves Age Distributions Regulation of Population Size Life History Patterns Human Population Growth Environmental Impact. Scope of Ecology.

allison
Download Presentation

Ecology of Populations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ecology of Populations Chapter 46

  2. Chapter Outline • Scope of Ecology • Population Density and Distribution • Population Growth Models • Survivorship Curves • Age Distributions • Regulation of Population Size • Life History Patterns • Human Population Growth • Environmental Impact

  3. Scope of Ecology • Ecology – what is it? • Definitions: • Habitat - Place where an organism lives. • Population - All the organisms within an area belonging to the same species. • Community - All various populations interacting at same locale. • Ecosystem – A collection of communities

  4. Ecological Levels

  5. Density and Distribution of Populations • Population Density - Number of individuals per unit area or volume. • Population Distribution - Pattern of dispersal of individuals within the area of interest.

  6. Uniform Distribution

  7. Random Distribution

  8. Clumped Distribution

  9. Characteristics of Populations • They tend to grow • Intrinsic Rate of Natural Increase (r)

  10. Population Growth Models • Exponential Growth • Biotic Potential • Environmental Resistance

  11. Exponential Growth Curve

  12. Logistic Growth • Logistic growth—indicated by an S-shaped curve • Difference between logistic and exponential due to environmental resistance

  13. Logistic Growth

  14. Carrying Capacity • Carrying Capacity is the maximum number of individuals of a given species the environment can support. • The closer the population to the carrying capacity, the greater the environmental resistance. • Biotic potential is having full effect and birthrate is a maximum during exponential growth.

  15. St. Paul Island Reindeer Population

  16. Mortality Patterns • Cohort --- all the members of a population born at the same time. • Survivorship---the probability of newborn individuals of a cohort surviving to particular ages. • Illustrated by Survivorship Curves

  17. Survivorship Curves

  18. Survivorship Curves

  19. Age Distributions • What proportion of population is in each cohort? • Age Structure Diagrams

  20. U.S. Age Distributions

  21. Regulation of Population Size • Density - Dependent Factors • Density - Independent Factors

  22. Factors That Affect Population Size Density Dependent Factors • 1. Competition • Intraspecific • Interspecific Predation Parasitism 4. Disease

  23. Factors That Affect Population Size Density Independent Factors Abiotic factors 2. Unpredictable, catastrophic events

  24. Life History Patterns • r - Strategists (Opportunistic) • Remember r=reproduction

  25. Life History Patterns • k - Strategists (Equilibrium) • Remember k=Karrying kapacity

  26. Human Population Growth • Human population has had an exponential growth pattern. • Doubling time currently estimated at 53 years. • Population Size • 1800 1 Billion • 1930 2 Billion • 1960 3 Billion • 2000 6 Billion

  27. World Population Growth

  28. Country Development • More-Developed Countries (MDCs) GR=0.1% • Less-Developed Countries (LDCs) GR= 1.6% • LDC population expected to increase from 5-8b by 2050

  29. Age Distributions • Age Structure Diagrams divide populations into three age groups. • Pre-Reproductive • Reproductive • Post-Reproductive

  30. The Demographic Transition • Stage I: high birthrates and death rates • Stage II: continued high birthrates, declining death rates • Stage III: falling birthrates and death rates, eventually stabilizing

  31. More-Developed Countries

  32. Less-Developed Countries

  33. Age Distribution of the World’s Population Population Structures by Age and Sex, 2005 Millions Less Developed Regions More Developed Regions Age 80+ 75-79 70-74 65-69 60-64 55-59 50-54 45-49 40-44 35-39 30-34 25-29 20-24 17-19 10-16 5-9 0-4 Male Female Male Female Source: United Nations, World Population Prospects: The 2002 Revision (medium scenario), 2003.

  34. Figure 7.2 World Population Distribution by Region, 1998 and 2050

  35. Environmental Impact • Measured in terms of: • Population Size • Resource Consumption Per Capita • Resultant Pollution

  36. Environmental Impact

  37. Review • Scope of Ecology • Population Density and Distribution • Population Growth Models • Survivorship Curves • Age Distributions • Regulation of Population Size • Life History Patterns • Human Population Growth • Environmental Impact

More Related